This invention concerns adducts of lignosulfonate and unsaturated fatty amines. More particularly, it is related to a hydrophobized lignosulfonate and a process for making the same by reacting lignosulfonate with an aldehyde and certain unsaturated fatty amines.
As used herein, the term "lignin" has its normal connotation, and refers to the substance which is typically recovered from alkaline pulping black liquors, such as are produced in the kraft, soda and other well-known alkaline pulping operations. The term "sulfonated lignin", as used in this specification, refers to the product which is obtained by the introduction of sulfonic acid groups into the lignin molecule, as may be accomplished by reaction of the lignin with sulfite or bisulfite compounds, so that lignin is rendered soluble in water. As used herein, the term "sulfite lignin" refers to the reaction product of lignin which is inherently obtained during the sulfite pulping of wood, and is a principal constituent of the spent sulfite liquor. The term "lignosulfonate" encompasses not only the sulfite lignin, but also the sulfonated lignin herein above described.
The reaction of lignosulfonate and an unsaturated fatty amine using an aldehyde as a crosslinker is one example of a Mannich reaction. The Mannich reaction is described in detail in Blicke, Organic Reactions 1, 303-341 (1942). Aminoalkylation of phenolic materials, such as lignosulfonate, is a special case of the Mannich reaction and has been described in numerous textbooks. For example, see March, Advanced Organic Chemistry: Reactions, Mechanisms and Structure, McGraw-Hill (1968), P.424. Lignin Mannich amines were disclosed as early as 1956 by Ball, Jr. in U.S. Pat. No. 2,863,780. The Ball, Jr. patent reveals a Mannich amine made by reacting kraft lignin with certain low molecular weight water soluble amines, and the utility of the Mannich amine as a corrosion inhibitor in hydrochloric acid solutions. Several U.S. patents have been subsequently issued for other lignin amines. For example, in U.S. Pat. No. 3,784,493, Giguere et al. discloses an amine lignosulfonate made by reacting spent sulfite liquor with formaldehyde and certain water-soluble amines, selected from the group consisting of alkylamine, cycloaliphatic amines, alkanolamines, and di- and polyethylene amines, at a pH of 6.5 to 7.0. Rachor et al. in U.S. Pat. No. 3,912,706 discloses a composition of matter comprising reaction products of lignosulfonate or kraft lignin, a secondary amine of from 2 to 8 carbon atoms, and a aldehyde, crosslinked with polyoxyalkylene, and the use of said composition as a flocculating agent. In the specification of the Rachor et al. patent, it is stated that the lignin obtained from some sulfite pulping processes may first need to be desulfonated to improve the flocculating efficiency. Ludwig in U.S. Pat. No. 4,017,475 reveals an aminoalkylated hydroxyphenylated lignosulfonate prepared by reacting a hydroxyphenylated lignosulfonate with an aldehyde and ammonia or a primary or secondary amine having from 1 to 22 carbon atoms. Said hydroxyphenylated lignosulfonate is a condensation product of sulfite lignin and phenol, cresol, xylenol, resorcinol, catechol, hydroquinone or naphthol. Probably because of the reduced water solubility of the hydroxyphenylated lignosulfonate (relative to unmodified lignosulfonate), the amination of said lignosulfonate is done in an organic solvent (such as 95% ethanol) according to the specification of the Ludwig patent. This is particularly true when long-chain alkylamines (e.g. octadecylamine and N-methyl-N-octadecylamine) are employed. The Ludwig products are classified as a cationic lignin as illustrated by the solubility characteristics of the products. The aminoalkylated hydroxyphenylated lignosulfonate has a limited water solubility at a pH between about 3 and 10, but is soluble at a pH below 3 and above 10.
Fatty acids are derivatives of certain plant oil and animal fat. The compositions of fatty acid products commonly used in commerce vary according to the source. Major fatty acid sources and their compositions are listed below:
__________________________________________________________________________ Palm Coconut Palm Kernel Tall Beef Soybean Oil Oil Oil Oil Tallow Lard Oil __________________________________________________________________________ Saturated Acids: Caproic Acid 0.5% 0.5% Capriylic Acid 8% 5% Capric Acid 7% 5% Lauric Acid 48% 50% 0.1% Myristic Acid 17% 2% 15% 3% 1% Palmitic Acid 9% 42% 7% 7% 29% 26% 6.5% Stearic Acid 2% 4% 2% 20% 11.5% 4.2% Unsaturated Acids: Palmioleic Acid 0.2% 0.5% 1% 2% Oleic Acid 6% 43% 15% 44% 42% 58% 33.6% Linoleic Acid 2% 9% 1% 37% 2% 3.5% 52.6% Linolenic Acid 2.3% __________________________________________________________________________
Fatty acids are hydrophobic oils, practically insoluble in water. Fatty acid-derived amines (fatty amines) are also oily, and water-insoluble. There is no viable chemical process in the prior art for reacting lignosulfonate and said fatty acids or amines in aqueous media. Tall oil is a by-product of the kraft pulping operation and amine derivatives thereof are particularly good materials for reacting with lignosulfonates which are also obtained as by-products of pulping processes.
It is, therefore, a general object of this invention to provide a reaction product of lignosulfonate and unsaturated fatty amines.
Another object of this invention is to provide an effective process for reacting lignosulfonate and unsaturated fatty amines in an aqueous solution.
A further object of this invention is to provide a lignosulfonate/fatty amine adduct that has unique performance characteristics and significant utilities.
Other objects, features and advantages of this invention will become evident from the following detailed description of the invention.